Blood is responsible for transporting oxygen, carbon dioxide, nutrients, hormones and proteins in the body, according to KidsHealth. The blood also carries glucose, ions, amino acids and waste products, such as urea, through the body. Red blood cells carry hemoglobin, a chemical that gives blood its red color.
Blood consists of red blood cells, white blood cells, platelets and plasma. Each of these components performs a specialized function, but blood has two basic functions. The first function is to guard the body against infections, which is a task relegated to the white blood cells, according to Kimball's Biology Pages. The second function is to transport various nutrients, food molecules and elements throughout the body. Red blood cells move oxygen, while plasma carries the nutrients and proteins.
Plasma is made up of mostly water, but it also consists of salts, lipids, proteins and sugar. Although plasma is part of the blood, it carries these materials from other parts of the body. The materials are mixed with the blood in other parts of the body, such as major organs, where they are converted, transported or eliminated. White blood cells make antibodies when the body gets an infection, but most of the cells in blood are red blood cells, notes KidsHealth.